Vehicles include internal combustion engines. Internal combustion engines provide torque as motive power for the vehicle. Combustion within the engine provides torque. Combustion may be accomplished in a variety of ways. For example an engine may utilize a homogenous charge compression ignition system (HCCI) in which an air fuel mixture is compressed at a temperature for ignition. Likewise, an engine may utilize a spark ignition system (SI) in which an air fuel mixture interacts with an electrical charge from a spark plug to combust.
A compression ratio within the internal combustion engine directs the amount of torque produced in the fuel efficiency of the vehicle. The compression ratio may be controlled using mechanism such as variable valve timing and throttle control. Also, a piston within the engine may affect the compression ratio. The geometry, shape, and stroke of the piston may be used to optimize the compression ratio and as such the fuel efficiency of the vehicle. Therefore, a piston having a geometry that improves combustion within the engine may be advantageous.